This proposal addresses Healthy People 2010's goal of eliminating racial disparities in healthcare. It also addresses the recent national emphasis on comparative effectiveness research to achieve the eventual goal of providing optimal care to all individuals. End stage renal disease (ESRD) is a growing health concern in the United States. Inequalities in multiple aspects of pre-ESRD and ESRD care among racial groups have been prominently highlighted in the last decade. Racial disparities can occur at multiple levels (individual patient, dialysis center and geographical region). A fundamental challenge in addressing racial disparities is to unravel the levels at which racial disparities occur and to identify the contributing factors at each of these levels, before corrective actions can be taken. The overall objective of this application is to dissect the causes of racial disparities in the processes of care and clinical outcomes in depth at the county and dialysis center levels for patients on chronic hemodialysis. This will be accomplished by applying advanced hierarchical (multilevel) statistical models to systematically examine the racial disparities in various performance measures across dialysis centers and across counties in the U.S. and uncover the sources of these variations while controlling for patient characteristics. We will examine a number of measures corresponding to important processes of care, including anemia management, care by specialists (nephrologists, dietitians) and vascular access preparation prior to ESRD therapy, as well as dialysis dose, anemia management, and preventative care at the ESRD stage. We will also examine the racial disparities in clinical outcomes (hospitalization and mortality) and relate these clinical outcomes to the disparities in care indicators. Aim 1 will assess the racial disparities in the processes of care both at pre-ESRD and ESRD stages, and clinical outcomes within and across U.S. counties, and examine to what extent the county-level variation in disparity can be attributed to county characteristics (e.g., minority composition, socioeconomic status). Aim 2 will assess the racial disparities within and across dialysis centers focusing on the ESRD care and clinical outcomes, and relate the dialysis center disparity level to center characteristics (e.g., ownership status, facility size, and clinical practice). The expansiveness of the United States Renal Data System augmented with the Area Resource File and the Census Zip Code Files provides invaluable data to accomplish these Aims. This study is designed to enhance our understanding of how the characteristics of geographical region and dialysis center contribute to the racial disparity in the care processes, and how the care processes, geographic region, and dialysis center interact in influencing clinical outcomes. The results of this research are critical for the development of more focused healthcare policy and interventions aiming at eliminating racial disparity in pre- ESRD and ESRD care. PUBLIC HEALTH RELEVANCE: The proposal will critically examine the variation in racial disparity in quality of medical care at the patient level, dialysis unit level and geographical regional level in patients with advanced chronic kidney disease. Understanding the sources of this disparity would help to minimize racial disparities and improve the care of patients with advanced chronic kidney disease.